


The Problem with Knowing the Future Is ...

by JRegni



Category: Avengers, Marvel Cinematic Universe
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Time Travel, Canon-Typical Violence, Captain America disapproves of the amount of language present, Dad!Steve, Dad!Tony, Domestic Avengers, Fluff, Gen, Gratuitous use of dashes and commas, Humor, Implied/Referenced Self-Harm, Implied/Referenced Torture, Kid Fic, Kids Are Scary, Language, Overpowered Kid, Pseudoscience, Superfamily, The Avengers Are Good Bros, Whump
Language: English
Status: In-Progress
Published: 2018-06-25
Updated: 2018-07-20
Packaged: 2019-05-28 14:24:29
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 13,884
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15051095
Author URL: https://archiveofourown.org/users/JRegni/pseuds/JRegni
Summary: The kid is nuts, they all agree, and certainly shouldn't be in the middle of a battlefield, but the kid knows more than any kid should know, and is able to do things no kid should be able to do.What choice do the Avengers have but to keep the kid at hand and out of trouble?





	1. ... it really tends to freak people out

**Notes for the Chapter:**

> The tags imply a lot of heavy material, and for sure there's plenty of messed up stuff that happened/s, but mostly this is intended to be a fic about the Avengers learning to be a family and raising a kid throughout the events of the MCU following the first Avengers film. 
> 
> This is the first work I have ever published, so any comments/feedback/advice are more than welcome.

 

 

The battle had been hard work from the start, and the onslaught of invaders seemed to have no end. Captain America and Black Widow fought side by side on the ground while Hawkeye provided cover from five stories up. Iron Man and Thor were each in the middle of their own dogfights in the sky, and Hulk was off in the distance doing his smashy thing.

An explosion knocked Cap and the Widow to the dirt, and Hawkeye wobbled unsteadily in his perch.

“Hawkeye, visual!” Cap shouted.

“I got nothin’ Cap, but whatever it was knocked out everything within a half mile radius at least.” He squinted against the clearing dust and smoke, unsure if he was seeing an odd shape in a pile of rubble or – “There’s someone in the middle of that, I think they're alive!”

Widow shouted something about a possible trap as Cap leapt into the mess and shoved aside a pile of sheet rock to reveal a scrawny, coughing kid.

“Hey, kid, you alright? What are you doing here?” The Captain held out a hand to help him up, observing for signs of injury. “You shouldn’t be anywhere near here.”

The kid staggered to his feet, brushing dirt off his filthy, torn jeans, shaking his head as if to clear it. The kid was young, bright blue eyes behind square rimmed glasses, a shock of dark hair poking out beneath a cap. He peered up at the Captain and then jumped back, hands held out. “Papa – what am I doing here? What are _you_ doing here – ?” He turned, catching sight of Widow, and gasped. “Wait – what happened? Nat, where’s Mom?”

The Captain looked to Widow, concerned. “Who’s your Mom, kid? What’s going on?”

“I don’t know what happened, Papa, you-n-Nat gotta find her, gotta help her, she was wigging out – whatever was up in the sky had her seriously freaked out.” He grabbed the Captain’s arm desperately, tugging.

Cap stared at her, mouth slightly open, unsure what to do. Black Widow hung back slightly, one hand at her side, not liking the kid’s complete lack of sense. Hawkeye walked up to them slowly, arrow nocked and pointed down.

The kid noticed him and laughed shakily. “You made it? I thought you – I really thought you were –”

The sound of thrusters came from above, and Iron Man sank to the ground, Thor close behind. The kid sagged with relief and let go of Cap, turning to Iron Man. “Thank fuck – sorry – Ma, you’re okay. Did you…” he faltered when the face plate lifted to reveal Tony Stark.

The kid took a step back, blue eyes turned to ice, smile gone. “Who are you?” He asked coldly.

Tony raised an eyebrow. “I can ask the same thing, kid. What are you doing in the middle of a war zone?”

“Who the fuck are you and where is my Mom?”

Tony paused uncertainly, and the other Avengers glanced at each other uneasily. “Kid, if you need help finding your Mom – ”

“ _Where the fuck is my Mom you creep?_ ” the kid snarled, breathing heavily, trembling.

Cap tried to soothe him gently, “Kid, please, calm down, we can help!”

“ _Get away from me!_ Who the fuck are you? What the hell have you done to them?” He turned to bear down on the Captain, as much as four-and-a-half feet could bear down on six-and-a-half feet of solid muscle.

Tony set a hand on his shoulder, and he jerked violently, screaming, “ _Don’t touch me!_ ” and launching himself at Iron Man, who was too startled to react. The kid ducked under his arms and leapt onto the suit’s back. A knife whipped out from fuck-knows-where and jammed into a seal on the suit, popping a panel open and exposing wires.

“Kid – guys, wait!” he shouted at the Widow and Hawk, who both had weapons aimed at the kid. Tony tried turning around to grab the kid on his back, but his arms were immobilized. “Shit, what the hell did you do to the suit? JARVIS?”

“Tell me where my Mom is, you sick bastard,” he spat. “And quit acting like you don’t know what I’m talking about, I know damn well – “

Before he could finish shouting, a giant hand yanked him into the air. The kid snarled and struggled, but the Hulk’s fingers wrapped completely around the kid’s thin body. “Dammit, Doc, not you too –”

Hulk turned the kid’s body to face him as the Steve and Tony shouted for him to not hurt the child. Bringing them face to face, the Hulk roared angrily.

Cap hesitated, afraid that the Hulk would snap the kid in half or throw him across the city. “Thor, get ready, the kid’s nuts but we can’t let Hulk kill him.” Thor nodded, spinning Mjolnir in his hand.

As the Hulk’s roar died down, the kid, astonishingly, roared back. Hulk – _the freaking Hulk_ – paused, bemused, clearly not having expected retaliation. He sniffed at the child curiously, then let out a great big snort.

“Yeah, that’s right, Big Guy, I’m okay, now let me down!” He grinned a little and added a small “please.”

Hulk grunted and released the kid, who dropped heavily to the ground with an “oof.”

“Thanks.”

The Avengers stood frozen in place, completely thrown off by the ridiculousness of the situation.

For a long moment the kid sat in the dirt, tears in his eyes, fighting for composure.  Finally he shook his head with a grimace and turned to Tony, still trapped in his suit. “Mister Stark, I apologize for incapacitating your suit and ask your permission to fix. Sir.”

Tony hesitated, not wanting the boy to touch the suit, but with little choice otherwise according to JARVIS. “Just get on with it.”

“Alright, sorry ‘bout this, I’m too short to reach from down here –" The kid scrambled onto his back, maintaining position with his knees, and reached a thin arm into the open panel. Tongue poking out between teeth, he reached into a pocket for a soldering iron.

“You carry around a soldering iron?” Stark asked incredulously, recognizing the sound and smell.

 “Never know when you’ll need field repairs. Sir.” He snapped the panel closed. “How’s that?”

Tony tried to move his arms. “Negative.”

“Ah, hold tight, gotta recalibrate the —” CLANG “—thingy.” He had slammed a fist into the back of the suit.

“Recalibrate — kid, what the —” Tony spun around to face the kid, scandalized, then realized he had _spun around to face the kid_. “What the hell did you do? Who the hell are you?”

The kid shrugged. “You can call me Artemis. Otherwise, can’t say. No really,” he added, flapping a hand, at the chorus of snorts and ‘ _are you kidding me_ ’ looks. “I’m not… from here. There’s some things I’ve got to do, some things I need to know, and then we can talk, so if you don’t mind I’ll be going now, don’t call me, I’ll call you—” he rambled, slowly edging away, only to be encircled by each member of the team.

“Guys, really, you don’t know it yet, but you can trust me. Miss Romanoff –"  He let out a stream of Russian, and Nat responded in kind. “ _Please, I can’t tell any of you who I am yet, there’s too much I need to know_.”

“ _Why should we trust you_?”

“ _Because I know you. You don’t know it yet, might not ever know it here, but someday you will be one of the people I care about most in the world, and I have to save you. All of you_.”

“ _You? An 8-year-old bo_ y?”

“ _Girl, actually, and I’m 11, thanks very much_.”

Natasha studied the child for a moment. “ _Who taught you Russian_?”

“ _You did. You also taught me hand-to-hand, and how to fire a gun. Barton taught me how to sign, archery, and the very subtle art of fucking with everyone while remaining lovable enough to not get strangled. Thor taught me about the cosmos and magic, and helped me translate it into science I could understand. Dr. Banner taught me the basics in biochemistry and field medicine, Hulk taught me not to take shit from anyone_.” She hesitated.

“ _And your parents_?” Natasha prompted.

“ _Taught me to question the universe, to discover everything there is to know about everything, how to build something out of practically nothing. Taught me the art of war, the art of strategy, the lie that is glory in combat, the true glory in defending what is right, and protecting what is yours_.”

Natasha raised her eyebrows. 

Artemis grinned mischievously. “ _You’ve seen weirder shit_.”

“ _So you’re from the future,_ ” she finally said.

“ _Yes_.”

She inspected the boy – no, girl – for a long moment, then nodded and stepped aside.

“Nat, what's going on?” Steve asked.

“She needs time and privacy. We’re going to let her have it.”

“You can’t just let him go!”

Natasha arched an eyebrow at him. “Her, and I just did.”

“She’s dangerous, she’s capable of knocking _me_ out of commission in a way I didn’t even know was possible.” Tony shook his head, “We can’t just let her _go_.”

Clint shrugged, “Nat trusts her, I’m not worried about it.”

Hulk grunted.

“I see no reason to contain this young warrior,” Thor said slowly. “I have many questions, but if she insists she cannot answer, there is no action to take but to wait.”

Steve looked on helplessly. “You called me…" He faltered.

“I’m sorry, Captain Rogers. Momentary lapse in sanity,” Artemis said, avoiding his eyes.

“No,” Tony said. “You’re dangerous, and if we don’t take you in, SHIELD will.”

“You afraid of a little kid, Mister Stark?” She grinned crookedly. “What’ll it take to get you to trust me?”

Tony stared at her. “What game are you playing, kid?”

She opened her arms to the heavens, “What will it take for some of the most powerful beings in the universe to trust an 11-year-old girl? What will prove me _trustworthy_? Untie the Gordian knot? Retrieve the Holy Grail? Determine the airspeed velocity of an unladen swallow and the migratory patterns of coconuts?” Clint outright laughed at that, and she _beamed_.

Tony glared at them both. “Maybe you can lift Thor’s hammer, that would prove you _worthy_ ,” he said, sarcastically.

The rest of the group stared at him, and then at the girl as she began to laugh. “Done. With my Lord Thor’s permission of course. I pick up Mjolnir, I get to go in peace  and return when I’m ready. If Mjolnir proves stubborn as ever, I shall gladly accompany you to your tower and answer what questions you might have. Within reason, anyway,” she added.

Thor frowned at the scrawny thing before him. “Are you certain, child?”

She grinned so widely that Thor hesitated.

“ _Can_ you wield it?”

 She shrugged, “Dunno yet. Haven’t actually tried. In theory, though…” She reached into her bag and pulled out a pair of metal gauntlets.

Tony made a disbelieving noise. “First, no cheating, secondly, where the hell did you get those?”

“First, you didn’t specify, second, I built these, and thirdly, they’re not like yours at all.” She tossed one to him. “No repulsors, no blasters, nothing fancy. Just an electric field generator.”

Thor laughed, booming, “Clever child, you most certainly have my permission and my blessing to attempt to wield Mjolnir.”

“Thank you, my Lord. Mister Stark?” She held out a hand, and Stark tossed the gauntlet back. After securing them, she wiggled her fingers, tiny white sparks generating over each finger, then clapped her hands once. As she pulled her hands apart, Bright blue-white lines arched between them, pulsing menacingly. She flicked her wrists, and they vanished.

Thor placed his hammer in front of her. “Don’t worry, child, I shall watch the lightning and draw it away if I must.”

“Thank you, Lord.”

“There is no need to call me ‘Lord.’”

“As you say, _Ellri_.”

Thor chuckled. “I’ll show _you_ ‘elder,’ _kind kvikindi_.” _Beastling_.

Laughing, Artemis planted both feet into the dirt and grasped the handle. For several moments, no one moved, hardly even breathed, just focused on the tiny slip of a girl who was so confident in her ability to do the impossible.

Her eyes closed, and her brow furrowed in concentration, but otherwise she did not move. Gradually, almost imperceptibly at first, tiny arcs of energy began to form around her hands. Jaw tight, she dug her heels deeper into the earth and clenched fists hard around the handle. Sweat formed at her brow, though she made no movement to pull.

 _Not_ _yet_.

She grit her teeth as the arcs around her hands and grew larger, crackling. Above, the clouds seemed to deepen.

Steve glanced up nervously. “Thor, buddy, tell me that’s you?”

“Nay, Captain, I have naught to do with this,” Thor answered solemnly.

Artemis was shaking now, muscles taut, sweat rolling down her face and neck. With a roar, she pulled, streaks of electricity flashing around and above her. For a brief moment, it seemed the hammer would not budge. The roar became a scream, and her feet sunk into the dirt. Mjolnir shuddered in her grasp and slowly rose. Her eyes snapped open, and they shone bright, hot-white blue.

“Ho-ly _shit_ , she’s gone super Saiyan,” Clint said, awed.

The static became loud cracks, became booming thunder, and the clouds overhead grew heavy and dark. Lightning flashed from the sky, striking way too close.

“You have proved your worth most admirably, _kind kvikindi_ ,” Thor said, “Release Mjolnir that you do not become overtired and lose control.”

Artemis roared again, Mjolnir held high and proud, as the thunder rolled and crashed. Lightning struck the hammer and enveloped her, the force of it making them all bear down to not be knocked back. Black scales slowly climbed up her arms like mail and the gloves on her hands burst into flame, scorching her hands, but she would not (could not?) let go.

“Child, _let go_!” Thor roared. He leapt forward, grasping Mjolnir’s handle, and a ball of lightning surrounded them both. The furious light and deafening roar forced the rest of the group to turn away, shielding ears or eyes. Thor pulled the lightning into himself, first from the girl, then the lightning surrounding them, and finally the storm clouds overhead. When the dust settled, Artemis and Thor stood in front of one another, each still holding onto Mjolnir. Artemis shook head to foot, breathing heavily, soaked with sweat, armor gone.

“Are you well, _smar_ _systrungr_?” _Little cousin_ , he called her.

She breathed a tiny laugh. “Is that what it’s always like? Being you, I mean?”

Thor nodded once.

“Right, never doing that again, thanks.” She laughed again, a bit shakier this time. “That was fucking terrifying, and I’ve been electrocuted before,” she said, hoarse.

“Indeed, lightning is a force beyond what I would expect most Midgardians to handle. If you could let go now?”

Artemis glanced down, surprised she still held on to Mjolnir. With an apology, she released the hammer, swayed slightly, then flopped bonelessly into the dirt before Thor could act. Swearing, Thor strapped Mjolnir to his side and scooped her up into his arms.

“Is she dead?” someone called.

Thor shook his head. “She breathes, but I fear she has over-taxed her body. It may take a long time to recover her strength, presuming she did no lasting damage to head or heart.”

Cap grimaced. “How’d she do it? We’ve all tried to lift the hammer before, so how’d this little kid manage it?”

“And what was with that freak storm?” Stark cut in. “Thor’s a god, alright sure, but some girl who can’t weigh more than 90 pounds soaking wet?”

Doctor Banner, having returned from Hulk, groaned and shuffled closer, Nat throwing a coat over his shoulders. “We need to get her to a hospital and make sure there’s no lasting damage.”

“No,” a small voice breathed, hardly even a whisper. “No hos’tal. Jus’ need to eat and sleep it off,” she mumbled, struggling to stay conscious. “Papa, tell ‘em, no hos’tal, no go’ment.” She drifted off, waving a hand vaguely, “’M okay, jus’…. Food…”

“Papa?” Clint asked no one in particular.

“One thing’s for sure,” Captain Rogers said, face set, “she stays with us until she’s well enough to take care of whatever she needs done. The kid’s got secrets, okay, fine, she can keep them. I’m not handing her over to SHIELD, not when we agreed she could go free. Stark, can you get Doctor Banner whatever he needs to help her?”

Tony frowned, seemingly ready to argue against the Captain, but instead nodded. “Should have everything we need at the tower. JARVIS can create any scans you need, Doc.”

“I still wanna know why the hell she keeps calling you 'papa,' Cap,” Clint muttered as they waited for JARVIS to bring in the quinjet.

 

 

 

 

**Notes for the Chapter:**

> 'Ellri,' 'kind kvikindi,' and 'smar systrungr' are Old Norse words taken from an online dictionary. Took some liberties with the translation of the second - it literally translates to 'young animal' but 'beastling' fits the mood better.
> 
> How did she lift the hammer? A combination of worthiness and manipulation of physics. Don't ask me to explain more, I certainly don't understand it.


	2. ... you don't want to find out if the butterfly effect is a real thing

**Summary for the Chapter:**

> Tony can't help it. He knows the kid won their bet, knows he shouldn’t pry, but he really really really wants to know who the kid is.
> 
> He almost immediately regrets his decision.

**Notes for the Chapter:**

> Chapter warning: mention of past torture and assault.

 

 

Artemis lay on a cot in the middle of the lab, attached to an IV and a variety of wires. Her filthy clothes were gone, replaced by a shirt several sizes too big that went well past her knees. The cap was also gone, hair pulled into a sloppy bun that had hidden so well under the hat. Several screens lined the air beside her displaying vital signs, heart rhythms, brain waves, and whatever else Bruce could think of.

In the corner, Bruce squinted up at a screen showing the latest blood results. “Doesn’t make sense,” he muttered. “Values dropped way too fast.” He ran a hand through increasingly messy hair, glancing up as Tony entered the lab.

“How goes?” Tony asked, offering a bag of grapes.

Bruce grabbed a small cluster and chewed thoughtfully for a moment. “Her heart stopped. No other signs, besides the collapse, but blood work points to cardiac arrest.”

“In a little kid? Was it the lightning?”

“Most likely. That’s not the weird part, though.” He pulled up a screen of lab values and pointed at one. “This is what points to cardiac arrest. Even small levels indicate a fatal event, but hers are insanely high. She should be dead.” He pulled up a second screen of similar numbers. “This was from a sample a half hour ago. Levels dropped a bit, not too improbable.” A third screen came up. “This was 5 minutes ago. Values are near normal. It shouldn’t be possible for that to drop so quickly. A few weeks, maybe, a couple months if she lived that long, sure, but a couple hours? This kid’s got a healing factor faster than even Steve’s.”

“Yet she’s still unconscious.”

“My guess is her body recognized the heart damage as priority and began to heal that immediately. Everything else could wait.”

Tony stared at the girl. “I don’t suppose you’ve done any genetic testing?”

Bruce frowned. “She lifted the hammer, she gets to keep her secrets. That was the agreement.”

Tony waved a hand. “We’re not trying to figure out her life story, just want to figure out what kind of enhanced she might be, compared to you or Cap, or even Thor, since she’s technically worthy of his powers.” He held out an arm. “Take my blood, compare hers to a regular, albeit genius, human. If we can figure out how her healing factor works, maybe we can help her get up and running faster. Right?”

“Right…” Bruce said uncertainly.

“Besides, she’s clearly underage. It’s in her best interest, really, and as in loco parentis –”

“Alright, Tony, you can stop trying to justify yourself.” He took a blood sample from Tony, as well as one from himself.

“JARVIS, have Cap and Thor come down here.”

“Of course, Sir,” JARVIS replied.

Bruce pulled up screens of each of their DNA samples, then retrieved a sample from Artemis as Thor and Steve arrived, Clint and Natasha behind, each finding a chair or stool to sit on.

Tony gave them a simplified explanation as Bruce drew samples from Steve and Thor.

Steve frowned. “We said she could go.”

Thor agreed with Steve. “Child or not, this is not honorable. We gave our word.”

Bruce glanced at Tony. “She’s healing quickly, but if I can figure out what makes her healing factor work, I can help her heal faster, better, with less risk of permanent damage.”

“Just want to help her, that’s all,” Tony added.

Bruce quickly added their samples before they could protest further, screens popping up as he worked. He lined them up side by side, Artemis’ screen in the center. With a frown, he made a casting aside motion at two of the screens, vanishing them from view. He ran comparisons, letting out a surprised ‘huh.’ He did the same with the last screen. His face smoothed over carefully, expression blank as he turned back to the others.

“Verdict?”

“Super soldier serum.”

Steve jerked. “How?”

“Partially – half, to be exact.”

 _Papa_ , she had called him. Steve’s mouth suddenly went dry. “That’s not – No. _No_.”

“That’s not all, is it?” Natasha asked.

Bruce met her eyes warily. “Half of her is biologically you, Steve.”

Steve swallowed hard, face pale.

“The other half is biologically Tony.”

Steve blanched further, Clint’s jaw dropped to the floor, and Tony laughed.

“Sure, Bruce,” he chuckled.

“Tony, I’m serious. Steve, I don’t know how she can be yours biologically, especially since she’s clearly older than you’ve been out of the ice, but it’s possible they could have spliced yours and Tony's DNA together and implanted it somehow – ”

A loud snort from the cot startled them all. Artemis was watching them, and apparently had been for a while. “Hardly been two hours since I won our little bet and curiosity already got to you?”

Bruce dropped his eyes, Tony shrugged unapologetically, and the others glared at the both of them.

Artemis smirked and sat up with a groan and fiddled with the IV in her arm. “How many is this?” she asked, pointing at the hanging bag of fluids.

Bruce blinked. “That would be the second.”

“D5? I guess it’s better than nothing, but I told you, I just need to eat. Freakin’ hungry now.” She pulled the bandages off her hands and hopped off the cot, weaving slightly.

Bruce rushed toward her, grabbing one arm to keep her from falling. “Your heart has been seriously damaged, you really need to rest - oh.” He examined her hand curiously, amazed by smooth, undamaged skin where previously there had been second-to-third degree burns.

“I’m hungry,” she repeated.

“We can bring you food,” Steve said.

“Trust me, it’ll be easier on everyone if I’m in the kitchen. I eat a lot.”

“We’ll bring you whatever snacks are in the pantry.”

She gave him a look, arms crossed stubbornly. “Captain Rogers, I know I look small, but on a good day I can eat more than you or Thor, and today is not a good day. I can probably eat half again as much as the both of you combined. Take me downstairs, let me stuff my face and get some strength back, and I’ll explain what I can. I’m sure you’re all just _dying_ to know how I could possibly exist. I really should just leave you all in the dark, but I guess now that the big secret is out in the open, there’s no point.”

“You’re not walking anywhere,” Bruce said, crossing his arms.

Artemis rolled her eyes. “Fine, whatever, but I demand a piggy-back. Much more dignified than being carried like a baby or thrown over a shoulder like a sack of potatoes. For me, anyway.”

The adults all stared at her, brows raised, ‘are you serious right now’ plain on their faces.

Clint was the first to kneel with his back towards her, face set. “Let’s get this over with.”

Artemis lips quirked as she clung onto Clint’s back. “Hi-yo silver, awaaaay,” she deadpanned.

Clint let out an amused huff, then let out an unenthusiastic neigh as he walked to the elevator.

 

In the kitchen Artemis sat surrounded by several piles of opened wrappers, fruit peels, dirty plates, and empty takeout boxes. She had gone through several boxes of snacks and fruit, and was well into devouring a 12-egg omelet before they realized she wasn’t joking about her appetite. Stark had quickly ordered three times as much takeout as he would have normally, and she ate damn near half of it.

Groaning, she finally set down her fork and hopped off the stool, stretching happily. “Thanks.”

“Feeling better?” Bruce asked.

Artemis nodded, grabbing her fifth or sixth water bottle and wandering towards the living room.

“Why does she look entirely too comfortable in my tower?” Tony muttered. Natasha hid her amusement carefully.

In the living room, Artemis hesitated for a second, glancing at the center couch, before choosing a spare chair off to the side as the others sat in their normal spots. She watched them get settled in for a moment and licked her lips nervously.

“My name,” she began, voice soft, “is Jaquelyn Stark, code name Artemis. Legally Stark-Rogers but Papa always said his name wasn’t as important to my future. I was born in 2007 to Captain Steve Rogers, code name Captain America, and Andrea Stark, code name Iron Woman.”

Tony couldn’t help but wrinkle his nose at that, and the girl carefully kept her gaze away from him.

“You don’t look five years old,” Clint pointed out.

“Before I crash landed in the middle of a battlefield, it was 2019.”

“So you expect us to believe that you traveled through time?”

“And space, yeah.”

Bruce shook his head skeptically. Hulk had seemed to like the kid, almost immediately trusting her, but he couldn’t wrap his head around what she was claiming.

“I know it’s hard to believe, but it’s the truth. How else do you explain that I’m half Stark and half Rogers?”

“Genetic experiment created by our enemies to destroy us all?” Clint said.

She frowned. “I thought I proved myself worthy.”

“Sleeper cells can believe a lot of things until they’re activated,” Clint pointed out.

“Hell’s bells, Birdbrain.” She glared at him as he smirked. “Not everything is a damn joke. There’s a war coming. Whether you believe it or not, it’s coming. Lots of people are going to die. Lots of _my_ people are dead - maybe all of them. They sent me back to save my life, maybe even to try to save theirs, but I ended up here instead. Don’t know if that was on purpose, but if I’m on this Earth and not my own, I can only guess they failed and my Earth is dead.”

She watched them all closely for a few moments. Not quite ready to believe her yet. She took a deep breath. “Captain Rogers. Born in 1920 to Joseph and Sarah Rogers.  Your father died when you were very small, but your mom raised you on his stories of the 107th.”

Stark made a rude noise. “No offense kid, but it’s not like that can’t be read in a museum somewhere.”

She regarded him coolly for a moment before looking at Steve. “She also told you stories of the old country, sang you lullabies in Gaelic. He would sing them to me every night he put me down for bed, or else he would play his old vinyl records. Billie Holiday’s your favorite. Ma usually sang Hey Jude, or AC/DC if she really wanted to annoy Papa. You never spoke much Gaelic, but when I asked him to teach me, we learned together. It would drive her crazy when we would speak it around her 'cause she was convinced we were conspiring against her. She was usually right.”

Steve felt something strange in his gut, wanted to believe every word. He couldn’t bring himself to look at Stark.

“Mom was the only child of Howard and Maria Stark. They died in a car accident when she was 17, right before she graduated from MIT. In 2001 she was kidnapped by a terrorist organization hired by Obadiah Stane. She nearly died from shrapnel in the attack and was saved by a man named Ho Yinsen. She and Yinsen built the first iron suit and she escaped, killing every last terrorist in the compound. Yinsen didn’t make it.”

She stared straight at Tony, who fiddled with the hem of his shirt but didn’t look away. She moved to stand in front of him, never breaking eye contact, whispering so softly that she doubted even Steve’s enhanced hearing could pick up the words, lips barely moving so that Clint couldn’t read them. “He never planned to survive your escape. His last words to you were to not waste your life. You crash landed in the middle of the desert and spent days hallucinating about your parents, about the soldiers who died trying to protect you. They told you it was your fault they were dead. You saw a little boy – ”

Tony turned away, heart pounding, stomach churning, but she continued.

“ – always saw the same little boy get hit by a bomb with ‘Stark’ stamped on the side. He cried for his mother and blamed you for killing him. You saw Uncle Rhodey, who said the first unhateful thing you had heard in weeks, and you laughed, nearly cried thinking you were finally dead and – ”

“Stop,” Tony rasped, eyes clenched shut, “please.”

“I know you, Tony Stark,” she said, quietly but no longer whispering, backing away. “You never told a living soul. Neither did my mom, not for a long time. She kept it buried away, until after the third time I was kidnapped. I was tiny the first two, didn’t remember any of it, but that time I remembered every damn second. It messed me up bad. We traded nightmares. It… helped.”

Tony Stark nodded, then excused himself, hands shaking as he walked to the elevator. He gave her one last look, face tight, as the doors closed.

“I’m sorry,” she said, after a long moment of dead silence. “He hasn’t got – people ought to know. He shouldn’t be alone with that in his heart.” She looked at the others sadly.

None of them would look her in the eyes. None of them had any doubt left in their own.

 

Stark had disappeared for hours after, and it had taken a call to Pepper to bring him out again, eyes bloodshot, smelling strongly of liquor. Artemis had apologized, stressing the need for them to believe her, and he had grinned (looking like a cornered animal, but grinning nonetheless) and waved the apology away.

In between, Bruce had gone back to his lab with another vial of blood (“You’re not gonna find anything you don’t already know,” she had said) and Thor had gone back to Asgard to seek counsel. Steve, Clint, and Natasha remained in the common room, asking question after question about the future.

Artemis was exceedingly patient, giving pieces of answers where she could, adamantly silent whenever she couldn’t say more.

“You said there’s a war coming?” Steve asked. “Shouldn’t we do our best to be prepared?”

“And something about the end of the world,” Clint reminded helpfully. “Be nice to not let the apocalypse happen.”

“I told you, there’s a lot I need to know. I can’t just tell you everything that’s gonna happen, messing with events will only lead to a future that I don’t know, and I won’t be any help if that happens.” She clenched her fists. “There’s a lot of crap coming your way, and I don’t know what good would come of me warning you of all of it.”

“Can lives be saved if you do?” Steve asked.

She jerked, somewhere between a shrug and a nod.

“Are we talking butterfly effect, if you save one life that could lead to a whole shitstorm of events that could lead to a worse future?” Clint asked.

Steve frowned. “I don’t see how stopping an attack on a city before it starts could be a worse future. Any situation that leads to mass casualties is the worse option.”

She shook her head. “Trying to end a war before it starts never turns out well. It’s nice to think optimistically but the universe doesn’t work that way. We like to think we shape our own futures, but we don’t have the luxury of creating our future so much as we pick the option that seems to suck less.”

“Nihilistic,” Natasha said, almost smiling. “Are you sure you’re not Russian?”

Artemis snorted. “I’ve been kidnapped five different times. One of those turned into a bigger shit-show than most and I was dragged back and forth across South America for _months_. I’ve seen some shit, done some shit, and it fucked me up bad.”

She stared at her knees for a moment. South America had been hell. Originally, they had told her that she had been kidnapped for ransom – surely the Stark heir would be worth billions? – but it didn't take long to realize she had been captured by Hydra for experimentation. She was brainwashed, beaten, and tortured, bones broken and rebroken, flesh burned, cut, and stabbed as they sought her limits. It wasn’t until they began to starve her that she stopped healing so quickly, and after that it became a game of how long they could leave her broken until death seemed all but certain. Then they would feed her, patch her up, let her heal, and start over.

Four months later the Avengers and SHIELD swooped in, guns blazing and found her half dead, barely beginning to heal after the last round of torture. Her mother and father cried. Full-fledged agents with years of field experience cried. Even Hulk howled in misery and rage when he saw her, and it was six weeks before reports of the Hulk destroying some outpost or another stopped reaching them, and another month before Bruce returned to New York.

Her, though? Nothing. She spoke when spoken to, ate, drank, and showered when told to, attended therapy sessions when asked, but otherwise there was an empty child living in the tower. Less than a month after returning home from the hospital she disappeared, careful to disable the GPS chip implant. She watched the city pass her by, hiding on rooftops and alleyways, sleeping under bridges or on the edges of homeless camps. She was harassed occasionally by a few of them, but a few broken bones later they learned a healthy respect and let her be.

A man attacked her once. He had her pinned against a wall, one hand around her throat, and she pondered whether ripping his dick off or carving something crude but descriptive on his forehead would send a better message. Both, she decided. Before she could do either, a scrawny teenager tackled him to the ground, knocking the asshole senseless when he slammed his head into concrete. The teenager recognized her, bought her a hotdog, got her to talk a little, then took her back to Stark Tower.

The experience hadn’t exactly healed her, didn’t even come close, but it had introduced her to her best friend, the kid who would end up fighting by her side in countless battles, who would save her life (and vice versa, though she had saved him three more times than he had saved her – but who was counting anyway), who would end up dying to give her cover instead of going through the portal three days later with her as originally planned.

She scowled at the looks on their faces. “I didn’t tell you that for the attention, and I don’t want your pity. My point is, yeah, it fucking sucked, and yeah, I’m fucked up, but I wouldn’t change a damn thing if it meant I’d never met – ”

She stopped herself. Spoilers.

“If you could save a hundred people today, but died in the process, what would happen to the thousands of people you were supposed to save tomorrow? A single life is priceless, a hundred even more so, but how do you weigh the hundred against the thousands?”

Steve’s jaw clenched. He understood the point she was trying to make, but the idea that she was willingly turning away from heaven-knows-how-many lives for fear of what might be weighed heavily on him. “So what do we do?”

“You keep doing what you’re doing. Keep training. Learn to be a team.” She shrugged. “I don’t exactly have a guidebook for this.”

“What will you do?”

“Me? Watch for signs. Get ready. Help where I can.”

“I thought you wouldn’t be getting involved.”

“I’m not gonna actively seek out every threat I know is out there. Doesn’t mean I won’t do what I can when the shit hits the fan.”

“Anyone ever tell you you cuss way too much for a Rogers?”

“Shaddap, Clint,” Steve and Artemis said at the same time.

 

 

 

 

**Notes for the Chapter:**

> Special shout out to Fairly Odd Parents for teaching me what "in loco parentis" is. Thanks, Catman.
> 
> Bruce has advanced medical training because plot convenience.
> 
> Super soldier serum plus high levels of hormones present in any human child equals a fast metabolism, an exponentially faster healing factor, and a resulting prodigious appetite.


	3. ...it's annoying having to keep stuff hidden from the primitives

**Summary for the Chapter:**

> It’s hard getting used to this new earth that looks and sounds and feels identical to her own, but is missing the most important thing about her world:
> 
> Family.

**Notes for the Chapter:**

> I have worked on about a half dozen other chapters before actually getting far enough on this one to post because I couldn't get it quite right. Still not entirely satisfied with it, therefore this chapter is much shorter than I would like. The next couple chapters will be posted fairly soon.

 

 

Later that night, Artemis let herself be led to a guest room on a top floor. It was minimally furnished and the walls were bare, no pictures, no artwork, no jokingly framed holes near the ceiling.

(“ _how the hell did you idiots manage that?_ ” a memory echoed)

Her things sat on the desk near the bed: a phone, a tablet, glasses, her bag of holding, and her freshly washed, utterly destroyed clothes.

The bathroom was fully stocked, a pair of gym shorts and an SI shirt folded neatly on the counter. She showered quickly, scrubbing dirt out of skin and hair, pulling on the clothes once she had dried off somewhat. She frowned at the clothes, the shirt hanging loosely and the shorts reaching her shins.

It was nearing midnight. Normally she would have long since been asleep, but she didn’t feel remotely tired despite the thoroughly exhausting day she’d had. She tossed her phone and tablet on the bed and collapsed next to them, glasses in hand. Briefly she considered trying to call her parents, immediately dismissing the idea as pointless and stupid. Instead, she examined the glasses carefully for damage and, when satisfied, put them on, running her forefinger across the left end piece. A soft chime indicated her print was accepted.

 **hi artie** , the lenses displayed in front of her eyes.

“JARVIS,” she called.

“Yes, Miss…?” the AI responded, hesitating slightly.

“Don’t worry about names, J, call me whatever you want. I have S-Stark’s word on my right to privacy, right?”

“Correct.”

“So anything I do will be kept secret. Assuming it isn’t interpreted as an imminent threat to the Avengers or anyone else, of course?”

“…Correct,” JARVIS said slowly.

“That extends to my personal property as well?”

JARVIS was silent.

“JARVIS, I know you have no clue how to deal with me, and I know my word means nothing to you yet, but I promise, I mean no harm to M-mister Stark or anyone else. You know I’m from the future, and so’s my tech. I’m not saying I don’t wanna share, but the less I interfere with the natural progression of things, the better off we’ll all be. No unintended consequences. Besides, it’s only a few years away, SI will catch up soon enough.

“You ask that I not analyze and share data regarding your equipment.”

Jax nodded.

“Very well. So long as you prove to not be a threat, no data will be reported to Mister Stark.”

Jax grinned. “You left out the ‘no analyzing’ part, J. Never mind, it’s cool.” She tapped the frame of her glasses. “Come on out, bud. JARVIS, meet APOLLO.”

A new voice seemed to come out of the glasses, young, probably male. “Hey J. Not-J. New-J. Other-J?”

“APOLLO is my personal AI. I reproduced your code and added my own touches. He does pretty much everything you do for Mister Stark, except he’s not linked to this tower so he can’t do much here yet.”

“Yet?”

“Well, once my stuff is connected to your servers, he will be too.”

“Apologies, but I don’t believe I can or should allow that to happen without consulting Sir on the matter.”

She shrugged. She understood the AI’s hesitation, but she also didn’t think Tony Stark wanted to deal with her any time soon. “Fair enough. We can discuss it in the morning. Or whenever he wakes up. For now, can I borrow you? I’d like to read up on current events.”

She made her way through several months’ worth of news stories from major outlets until the sky began to brighten. APOLLO told her cheerily that it was nearly 6 in the morning and she groaned, staggering out of the rumpled but otherwise unused bed. Barefoot and bleary-eyed, she made her way down to the common area for caffeine.

Steve was threatening the coffee machine as it beeped ominously at him. “I swear, Stark made you refuse to work for me somehow, I just know it,” He muttered darkly.

Jaquelyn cleared her throat and motioned for him to stand aside. With a minor adjustment and the press of a few buttons, coffee blessedly began to flow.

“Thank you.”

She sat at the counter and laid her head on the cool surface, flashing a thumb up.

“Too early?” Steve asked, smiling when she grunted at him. He filled up three mugs, setting one in front of her, sipping from the second, and holding out the third just as Bruce walked into the kitchen.

Bruce took the mug gratefully, staring as Artemis chugged her entire cup. He failed to hide his amusement when Steve refilled her mug and she chugged that one down as well. His amusement became tinged with concern when she finished her third cup. "Did you not sleep well, Jaquelyn?" he asked kindly.

She took a sip from cup #4, contemplating. “Jax,” she said, finally. Bruce tilted his head, questioning. “Call me Jax. Or Artemis. No one calls me Jaquelyn unless something’s suspiciously on fire.”

Both men laughed. “Jax then.” They sat in silence, nursing their drinks, and Natasha joined them.

“You’re up early. Did you sleep well?” she asked.

Jax shrugged, polishing off cup #4.

Steve excused himself for his morning run and Bruce headed off to the lab. Natasha poured herself a mug and observed Artemis, who was staring at her cup. The girl's eyes were glassy and her entire body drooped with exhaustion. Natasha doubted she had slept more than a couple hours, if at all.

Clint stumbled into the kitchen, grunting at them. Natasha smiled fondly and Artemis grunted back, reaching for the pot to refill her mug. Clint poured it for her, surprisingly not spilling any, and reached for a mug, thought better of it, and drank directly from the pot. Eventually the two spies left as well, leaving Jax alone in the kitchen. She made a fresh pot of coffee and took cup #6 to the living room and sat down on the center couch, listening for someone else’s arrival.

Long after cup #6 was gone, the floor remained empty.

She sprawled onto the couch, one leg dangling off the side, asking JARVIS to pull up a screen and idly scrolled through it. Losing interest, she vanished the screen and rolled onto her stomach, eyes closed. An hour later, still wide awake, she sat back up and turned on the television, flipping through several hundred channels before growing bored and digging through the game cabinet instead.

What year was it again? 2013? She dumped out the entire contents of the cabinet onto the floor, searching for that one title, which had to be there unless Sam and Clint had already gotten it banned – she stopped, nauseated by the sudden wave of homesickness. She stuffed the games back in the cabinet haphazardly and threw herself back on the couch, blinking tears away.

She moved her lips soundlessly, talking to APOLLO, who was capable of understanding her by tongue and lip movement alone. “APOLLO, run through my playlist, and don’t play anything released after late 2012.”

“Sure, but that leaves out a big chunk of your collection,” APOLLO responded through a bone conduction speaker embedded in the temple tips of her glasses. Jax had finished the glasses not that long ago and was glad for the extra privacy now.

“I know, but I might as well get used to it.”

The first song was classic rock – one of the songs her mother liked to sing randomly. Jax pressed her face into the couch and groaned loudly, sound slightly muffled by the cushion. “APOLLO, you asshole,” she said out loud, rolling onto her back.

Tony Stark looked at her curiously as he walked past her to the kitchen. “Do you regularly swear at Greek gods for no apparent reason? Seems like asking for trouble, doesn’t it?” he asked, unable to help himself.

Jax sat up quickly, embarrassed. “Mister S-Stark, I –”

Tony’s lip twitched up in a small smile. “Sorry. For all I know, it’s a future thing, who am I to judge?” He grinned wider, posture relaxed, none of the previous night’s tension present except that he couldn’t seem to look her in the eyes.

That was okay, though. Neither could she.

She trailed after him to the kitchen with her empty mug, refilling it after Tony poured himself a cup. After a few minutes of uncomfortable silence, Jax said, “I have a favor to ask,” at the same time as Tony asked, “I hear you have a request?”

They blinked at each other for a moment, and Tony raised a palm in an ‘after you’ gesture.

Jax fiddled with her shirt sleeve as she explained APOLLO’s existence and her need for access to the tower’s servers so that she could have him run comparisons of the two timelines, not to mention her need to fix her electric field-generating gauntlets, plus she had at least five different ideas for upgrades to her tablet and its holoscreen projector –

Tony waved a hand, stopping her mid-babble. “Fine, fine. Do your thing. JARVIS will monitor for any blatantly dangerous activities, otherwise you do you.” He looked at her briefly, turning away when her eyes glanced up to meet his. “I expect this means you’ll need lab access?” She nodded, and they discussed the equipment and material she would need, all of it already available.

Afterwards, Tony excused himself, and Jax called after him. “Mister S-Stark,” (why couldn’t she just say the name?), “wait.”

He stilled but did not turn to face her.

“I just wanted to say I’m sorry. For bringing that up. Really, I am.”

“You don’t have to apologize again.”

“I-I know, but I wanted to make sure. It never stopped hurting you, I can see that, and I prob’ly made it worse. I’m sorry for that.”

Tony shrugged. “You did what you had to do. You’re right, I can’t think of anything else that would’ve made me tr- believe you so quickly.” He shrugged again and left.

Jax stared at the spot where he had stood, chewing her lower lip. Just looking at Stark hurt deeply.

Everything in the tower looked the same, down to the stupid scorch marks on the ceiling (Jax had been the one to start a grease fire in her kitchen – she idly wondered who had done it here) and the stupid magnets on the fridge (why did a house with no children need alphabet magnets?). The other Avengers looked the same, talked the same, started their mornings off the same. It was all the same.

Everything but Stark.

The resemblance was definitely there, which is how she realized she wasn’t in the right universe once she had calmed down a bit on the battlefield. Even the mannerisms were similar – the tiny appreciative sigh that came after the first sniff of coffee, mug turned just so each time it was set down, the way restless hands fidgeted with anything and everything within reach. So close. So similar. If she closed her eyes and tuned out his voice she could almost believe she was home.

Except for –

But he wasn’t –

Dammit.

 

She staggered back to the guest room, determined not to let anyone see her cry. For several moments she leaned against the wall, breathing deeply, forcing herself to calm down. APOLLO was asking her something. She muted him.

Everything was the same, except it were it mattered.

She gripped her thighs so hard that her nails left angry marks on her skin and cried.

 

 

 

 


	4. ... special effects used to suck

**Summary for the Chapter:**

> Jax is homesick and feels out of place in the past.  
> Steve can relate.

**Notes for the Chapter:**

> This is possibly one of my favorite chapters I've written yet, followed closely by the next chapter. What can I say? I'm a sucker for dad!Steve.

 

 

Having decided there was no point in playing nomad when there were no big secrets to maintain, Jax officially took up a guest room on the common floor of the tower. She stayed mostly out of the way, quietly observing, often typing notes or doodling on her tablet. She especially liked to watch each Avenger in their natural state: Tony and Bruce in the lab, Steve and Natasha sparring or (mostly Natasha) yelling at Clint, Clint at target practice or being yelled at, Thor (when not in Asgard or with Jane Foster) learning about the customs of Midgard.

Sometimes, though, she would disappear for hours at a time, reappearing long enough to raid the fridge and then go back to hiding somewhere in the tower. When asked, APOLLO would refuse to disclose her location, saying that she was in no danger and did not wish to be disturbed unless it was an emergency.

One of these times, Steve found her on the roof. She had been crying, he noticed. Quietly, he sat next to her, one hand open and inviting on his leg. He contemplated half a dozen stories that could possibly cheer her up before deciding she was probably sad enough to not care to hear about all the times he and Bucky got into some tremendously stupid shit. Besides, it was fairly likely she had already heard all the stories.

“I lost a lot of good people in the war,” Steve finally said. “But when I woke up from the ice, I felt like I had lost everything. Not just people – this entire country was so different. I was so lost, felt so alone. I hated it, hated everything… I wanted to die.” He watched the sun as part of it hid behind the tops of buildings. “This city… As much as it’s changed, it’s still _mine_. I can understand what it’s like, waking up in a new world, feeling out of time and place, but I can’t begin to imagine what it’s like being in a new world that’s not the one you know but looks identical. I don’t know what it is to look at copies of the people you’ve loved your entire life, but they don’t know you.”

Tears streamed down her face, and she made no move to wipe them away, only stared at the city below. Steve reached for her hand cautiously. The moment they touched, she threw herself into his arms, sobbing. He held her tightly, one hand cradling her head, as she cried herself dry.

“They’re all gone,” she sobbed. “Why would they do this to me? Did they know that they would all die and I’d be left all alone?” Her grip on his shirt loosened, and she looked up at him. Steve felt his heart ache the pain on her young face. “I didn’t even get a chance to save them,” she whispered, burying her face back into his chest.

Steve had no words, no inkling of how to comfort her other than to hold her. If he hugged her any tighter, he was sure she would break.

“You won’t,” she said, as if she’d heard him. “You hesitated,” she explained when he pulled back to frown at her. “You – he was always afraid of hurting me or mom.”

She sniffed and sat back, breaking their embrace, watching the sun disappear behind the city. “This was our spot,” she said after several minutes, gesturing at where they sat. “He liked coming here to be alone. When I was born, he would bring me up here and would just hold me. Scared Mom half to death the first time she caught him sitting over the edge with me, but JARVIS had us covered.” She smiled a little at that, and Steve couldn’t help smiling back.

“It was our thing. Before or after a mission, on special days, or just ’cause, we’d come up here and watch the city. Sunset was always the best.” They watched the last of the sunlight disappear and the city lights come to life.

Steve set his hand on her shoulder. “I can’t replace him,” he said gently, “but I could come up here with you – if you want. We don’t have to talk or anything…”

A small hand reached up and settled on his. “Thank you. I think I’d like that.”

 

After that evening, the two slowly became inseparable. The way they bantered, the way she called him “Steve” instead of “Mister” or by rank like everyone else was instantly noticeable. Gradually, she began to follow him everywhere around the tower, and vice-versa.

They were always the first ones awake, and she would join him on his morning runs, keeping up if she had eaten a decent snack but falling hilariously short once it was nearly time for breakfast. She would help him work the coffee machine and taught him to make a decent breakfast spread (thank fuck, said everyone else). They sat together at the table or at the kitchen counter for every meal, whether everyone else joined them or not.

Every Thursday they would take over the living room and plow through Steve’s list of movie suggestions (he asked her for suggestions once, but she said most of them hadn't been released yet). Steve was surprised to realize she also hadn’t seen several of the films on the list, only the ones he really loved.

“Your list was several years ahead when I was finally intelligent enough to join you,” she explained, “I hadn’t been around for most of this list.”

Everyone, including Steve (and wasn’t he just thrilled at being able to rib someone else for a change) teased her for being so young and naive, but Steve was secretly pleased to have someone to share his list with.

And if no one was gonna mention how she referred to her Papa as “you,” well, that was just fine with him.

 

They often trained in the gym together, but their first attempt at full-contact sparring was a disaster. Steve was so hesitant to do much more than block her strikes and throw half-hearted punches that she yelled in frustration, picked up one of Steve’s 400-pound punching bags, tossed it in the air, and kicked it so hard that the damn thing exploded. Steve, and Nat and Clint who had been on the other side of the gym, stared in awe as sand showered them.

“And to think my testicles had _just_ stopped retracting in fear every time you walked into a room,” Clint said, yelping when Nat smacked him.

Jax rounded on Steve. “You’ve seen me take a punch before, stop babying me, Papa!” she snapped, freezing when she realized what she said.

Steve’s shock at the display of force melted into something soft, then became sad, almost wistful when she fled.

“Steve? You okay?” Nat called. He nodded, then asked JARVIS to send in the CHAI bot.

(Cap has anger issues, Tony had said after the fifth punching bag had been destroyed. Shortly after a glorified vacuum cleaner robot appeared in the gym. It also made tea, for reasons Steve couldn’t fathom, but Tony had thought hilarious.)

Steve debated going up to the roof, then decided against it, thinking she would want time to herself. When she skipped lunch, he felt a twinge of guilt.

“Not like her to miss a meal,” Bruce said. “Should we take her something?” He glanced at Steve.

“She needs space,” Nat said, and that was that.

Steve sat in the common area for hours, blasting some of their favorite cartoons. When the stupid coyote falling off a cliff failed to draw her out for the hundredth time, Steve made his way to the roof, disappointed to find it empty. After, he paced the hall in front of her room for a while, periodically pausing at the door, reaching up to knock, then deciding against it and continuing his pacing.

When she didn’t show up for dinner, Steve stared at the empty chair next to him, practically pouting.

“Everything okay, Cap?” Tony asked.

Steve’s head snapped up and he bit back an angry response at the genuine concern on his face. Well, hot damn, Stark cared? He shrugged, then stood and began to load up a plate with food.

He hesitated in front of the door, then knocked firmly.

No response.

He knocked a bit harder, ears reddening, hyper-aware of the way the table was still silent.

Nothing.

Steve banged on the door, rattling the frame. “Dammit, kid, if you don’t open this door –”

“Artie says to watch your mouth and would like you to know that the door has been unlocked all afternoon,” APOLLO said coolly. “And _I_ would like to thank you for finally making an appearance.”

Steve scowled at the ceiling and entered. The room was dim, lit by the glow of a 3D holoscreen projection in the middle of the room. Jax lay bundled up in the middle of the bed, watching the scene in front of her. Her eyes were bloodshot, cheeks bright red. Steve set the food aside and sat on the edge of the bed.

The projection was of a group of people around a dinner table. He recognized himself, older, hair longer, a bit of scruff growing on his face, sitting next to Jax, both wearing Santa hats. She was talking to someone next to her – the face was blurred. A teenage boy, he guessed. On the other side of Steve was a dark-haired woman, brown eyes and smile unmistakable. Her features were softer, less wrinkled, but definitely favored Stark.

She was beautiful.

Steve stared at the three of them for an eternity, heart aching.

Other faces were blurred, but there were many familiar faces, too. Nat looked strange with blonde hair, Steve thought. Her face was exasperated, hands thrown up in the air, and Clint, who sat beside her, was looking pointedly at the ceiling with his hearing aids sitting on the table in front of him. Steve couldn’t help but smile. Thor’s seat was empty, as was Bruce’s. Colonel Rhodes seemed to be in the middle of a passionate discussion with Sam Wilson, the guy who had been trying and failing to keep up with them on their morning jogs. Steve made a mental note to invite him over for breakfast some time, liking how comfortable the veteran seemed among the group. He fought a laugh when he spotted Fury, whose eye patch was painted to look like a Christmas ornament.

“I made that for him. He refused to wear it until I swore I would stop sneaking in his office and booby trapping his desk and chair.” Her lip twitched. “It only lasted about a week.”

“When was this?”

“Last Christmas. Six years from now. When we started getting signs that something was happening, I had APOLLO download recordings so that I would have something to remember the ones we lost.” With a grunt she sat up, blanket still wrapped tightly around her. She looked up shyly.

Steve scooted closer to her, gratified when she laid her head in his lap.

“The blurry people?”

“You don’t know them yet.” She sniffled a little and winced. “Fuck, you even smell the same.” Her eyes teared up a little. “I forgot you weren’t him. I forgot they’re all dead. I forgot I’m stuck here, alone.” Her voice broke.

“No, not alone,” Steve said, stroking her hair. “Never alone.”

“I wanted you to be him so badly. I miss him so much –”

Steve hushed her gently. “I know, kiddo. I’m sorry.” He turned her head slightly to look her in the eyes. “I might not be your father, but we’re still blood, right? We can still be family. I’m not trying to replace him, but if it makes you feel better, call me whatever you want. Anything you need, kid, I’m here for you.”

Steve swallowed against the lump in his throat when she held his hand. He had never had kids, probably wouldn’t ever he thought, glancing at deep brown eyes and a soft smile, but this kid who was so much like him, literally his own blood, had such a grip on his heart he was nearly overwhelmed with how badly he wanted this.

“We can be family,” he repeated. “It’s little, and broken, but still good.”

She sniffled. “Yeah, still good,” she echoed.

He reached over for the plate of food and sat it in front of her. “Now eat up, it’s Thursday.”

She obediently began nibbling, still laying down. “Can we watch that again?” she asked quietly.

“Sure, kiddo, anything you want.”

 

That night they took up their usual seats in the common room. Steve was grateful that no one asked any questions other than to offer snacks and drinks. No one commented on how she curled into his side, or how Steve had one arm wrapped around her, or how they both looked as though this was the best thing in the world (which it was, thought Steve).

No one said anything – although one or two were visibly stunned – at how _both_ of them began to sniffle, then outright cry at the end of Lilo and Stitch.

And if no one was gonna mention how she called him “Pop” when she bid him goodnight, well, that was just fine with him.

 

 

 

 

**Notes for the Chapter:**

> Why is it that movie night is always on Thursday? In my head I thought Thursday would be funny because it implies that they're including Thor in the journey through pop culture (Thor's-day), but it seems to be a running theme in a lot of different fics? /shrug


	5. ... five year old tech sucks when you know what the new stuff looks like

**Summary for the Chapter:**

> Tony doesn't know how he feels about Jax until he realizes the Littlest Science Bro could be a lot more fun than Green Science Bro.

**Notes for the Chapter:**

> I'm a sucker for dad!Tony, as well as dad!Steve. Although they will each have a parent/child relationship, I have yet to decide whether or not this will eventually become Steve/Tony. The story outline I currently have laid out could go either way.

 

 

Tony Stark didn’t know what to think of the smartass kid who had recently commandeered a corner of his lab. He had long since offered to set up her own lab in another area of the tower, but she spent so much time discussing the mysteries of the universe with Bruce that there was no point. He had a healthy respect for anyone, especially a kid, who’d been through as much shit as he had, but she just… rubbed him the wrong way.

It’s not that the kid was annoying – although she definitely could be, staring at him while he worked until he had to stop and ask if she needed anything (she would grin a little, but shrug and look away every damn time). He often wondered if he had been that annoying as a kid, then would ignore the way he automatically thought, nope, much worse. If anything, the kid was downright cute - a perfect mix of precocious and precious, mixed in a way that wasn’t half as aggravating as he had ever been.

She had a variety of tech on her at any given moment, similar to but leagues beyond any model SI had ever designed, and when asked she only said that she custom built it herself, and no, no one is allowed to peek for another three years. He itched to take them apart and see what she had come up with, or even to watch her work, but she had developed the aggravating habit of tinkering in the lab only after Tony had finally gone to sleep.

At first, he thought it was to avoid him (and no, that didn’t bother him in the slightest, thanks for asking) but when he asked Steve what she was working on and how much more material she needed because he could buy in bulk no problem but if he bought too much it would take up all the lab’s storage space and he had a supply of titanium coming in soon -

Steve shrugged and said he had no idea. Tony was baffled, thinking they were attached at the hip. Steve only said that she worked on stuff when he was busy with SHIELD. Otherwise, her time in the lab was spent discussing theories with Bruce or studying.

After that talk, Tony had JARVIS brief him on what subjects she researched (he also tried to have APOLLO and JARVIS _show_ him what she was working on, but the little shits had reached an understanding with each other and refused, even after he threatened to reprogram them into ass-scratchers and sell them to Hammer Industries). The research varied wildly: history, current events, law and politics, medicine, engineering, and an obscene amount of physics, among other things.

What had really caught his eye was her grasp on mathematical engineering. She had left notes laying around once, and Tony had been beside himself to see pages of equations explaining the mechanics of his Mark XLII’s prehensile technology. Other notables included the insane amount of physics fuckery required for Hawkeye to pull off some of his more impressive trick shots, as well as the amount of force Black Widow could theoretically apply on the average man’s skull with various muscles.

 

Tony had been exceedingly polite to Nat since _that_ particular discovery.

 

The kid was a freaking genius, likely even smarter than he was, and he hated himself for admitting that he really wished she would just  _talk_ to him.

Out loud.

 

To Steve.

 

Which is how he found himself face to face with one (1) sassy little Stark-Rogers sitting on an empty corner of his desk the following afternoon.

“Can I help you?” He asked roughly, feeling more than a little guilty at her barely-contained flinch. He cleared his throat. “Ah – sorry. What’s up, kid?”

She shrugged. “Just wanted to watch you work, if that’s okay.”

Tony was very much aware of how Bruce was side-eyeing him from his side of the lab, and how Steve was failing to pretend to draw over on Jax's side of the lab. Tony shrugged back, pulling up a holoscreen. “Sure, kid. Been playing with the repulsors, making them quieter and more efficient.”

“How do they work?”

Tony squinted at her. “Don’t you already know?” he asked, not quite accusingly.

“Nope,” she said, and Tony raised an eyebrow. “No, really. We had a rule. I couldn’t physically make or work on anything until I could prove I understood how it worked, which usually involved a lot of math. I never got a chance to play with the repulsors - I thought I had it once, but apparently I missed something, and I never got to finish.” She fumbled with the tablet in her hand, pulling up a large screen of equations.

It took Tony a while to spot it, but there were a few variables where she was clearly on the right track yet hadn’t quite reached the right conclusion. He began to explain one section, Jax clearly hanging onto every syllable, delighted, when Tony stopped mid-sentence.

“Wait, why?”

She looked up, startled, a pen cap poking out of her mouth, stylus scribbling furiously on her tablet. “What?”

Tony gestured to her notes. “Why is this a rule? You’ve got your own piles of tech, you’re clearly smart enough to build repulsors, why do you have to prove it first?”

To his surprise, she blushed.

“Used to be I only had to explain stuff out loud as I was playing with it, but –” She glanced at Steve, who had yet to begin drawing. “Y’know how you and Thor do that thing where you aim at Cap’s shield and use the blast to wipe out a group of enemies?”

“Yeah?”

“Why do you do that?”

Tony frowned. “The vibranium enhances the attack.”

“Yeah, by how much?”

Tony opened his mouth to respond, then shut it, blinking, startled to realize he didn’t have an answer. “A lot,” he finally managed. He hadn’t thought to find out how or why, just knew that it worked.

“Right, so I, uh, wanted to find out exactly how much. Are we talking exponential? What is the limit? Does the angle that you hit it at affect the force of the rebound? How are the repulsors enhanced compared to Thor’s lightning?” She paused briefly, looking almost shy. “What’s the difference between Thor’s lightning and Earth’s lightning and how would that difference skew the data?”

Tony felt his mouth drop open. “ _You didn’t_.”

“I did.” She grinned sheepishly, tips of her ears reddening.

At this point, Bruce and Steve had given up all pretense and were both facing them, interested. “What did you do?”

“Well, it was mid-August, and the forecast predicted a hell of a storm comin’ –”

“You Frankenstein-ed the lab?” Tony asked, scandalized and amused.

“Nah, I was on the roof landing pad.”

Tony closed his eyes, not sure he wanted to know (of course he wanted to know). “What happened?”

“I blew up the bar, shattered half the windows on the top eight floors, knocked out power to the tower, and launched the shield almost to Jersey.”

The men gaped at her and then burst into laughter, Jax’s face and neck growing steadily redder by the second.

Several minutes later, Tony finally managed to ask, “Jesus, what happened to you?”

“Got myself electrocuted and blasted fifty feet in the air, and then broke a few bones when I hit the roof.”

Tony chortled. “ _Jesus_. So what’d you learn?”

“Lightning is a scary motherfucker.”

“What else?” He nodded at her tablet.

“Well, I wasn’t allowed to look at any of the data for a while, first because JARVIS was mad at me for knocking him out, then because I was grounded for like, a couple days, but then no one could find the shield so I got to calculate the flight trajectory based on how hard the shield got hit…”

Tony looked at her expectantly.

“You’re right, vibranium enhances attacks by a lot.”

Tony groaned, head dropping back.

“I’m kidding, look.” She pulled up several screens of data, and they were off, discussing her findings.

He could get used to this, Tony thought. Bruce was great to have around, but in the lab he was content with research and theoretical application as opposed to his (and the kid’s, apparently) hold-my-beer-and-lookit-this attitude towards experimentation.

Having exhausted what little data they had on hand, they switched to contemplating ways of experimenting on the shield with the repulsors and with Mjolnir. Safely, of course, because Tony had no doubt that a half-super-soldier-slash-genius-slash-possible-demi-goddess could survive being electrocuted and eating shit at 120 miles per hour (again) but was equally certain Steve would recreate the blast on an unarmored Tony if anything happened to the kid, enhanced healing or not.

 

 

Three days later found them both rolling on the roof’s landing pad, eyebrows singed, laughing hysterically even as Steve, red-faced and bellowing, went on and on about _safety_ and _responsibility_ and how he shouldn’t get suckered into performing dangerous experiments by a child, and _for Christ’s sake Tony, are you an adult or not_ , and what if there was a call to assemble and they still hadn’t found his shield, which they didn’t even _ask_ permission to use –

(It took them nearly a week to track down the shield, which had managed to land in the middle of an empty field in Connecticut this time.)

(It took three times as long for Steve to stop side-eyeing them and muttering angrily every time he so much as looked at his shield.) 

Yeah. He could definitely get used to this.

 

 

 

 

**Notes for the Chapter:**

> Haven't gotten very far on the next couple of chapters, and don't expect to be able to work on this much due to personal issues. I will try my best to have another chapter posted by next weekend.


	6. ... birthdays suck when you know exactly how many are left

**Summary for the Chapter:**

> Tony’s birthday is tomorrow.  
> No wonder Jax was in such a funk.

**Notes for the Chapter:**

> Chapter warning: references to torture, self harm, and attempted suicide
> 
> Only a week later than I intended, and I had to cut off the chapter because I couldn't for the life of me decide where this was going. Will probably do a few more chapters showing the dynamics between Jax and the remainder of the team before moving into CA:TWS and AoU.

 

 

Jax felt as though she had barely blinked and several weeks had flown past. She still missed her home world terribly – even thinking about her family would form a lump in her throat – but she was adjusting.

 

For the most part.

 

The nightmares, which she had struggled with forever despite intensive therapy, were as terrible as ever, and she spent many sleepless nights huddled under blankets. One such night the bare walls of her room felt too much like a prisoner’s cell, and she curled up on an armchair of the empty common room, mostly hidden from view.

This newest nightmare had been a muddled mess, taking her back to the last time she had seen her mother. Her anguished face morphed into Tony but not Tony – she couldn’t imagine his face ever twisting into such anger and hatred. Not-Tony towered over her with a hand raised to strike, and then she was back in South America

_ribs cracking and breaking under the sharp force of heavy boots_

_screaming hot brands pressing into bare thighs, smell of burning flesh choking the air_

_the skin of her fingers and hands slowly being peeled away from muscle and bones by a wicked sharp knife_

_the horrible feeling of drowning, lungs screaming for air_

_pain_

_exhaustion_

_hunger_

_so much pain_

_please make it stop_

_fingernails clawing into wrists in a moment of weakness, eager to spill her own blood, to end it all_

_it hurts it hurts ithurtsithurtsmakeitstopmakeitgoaway –_

She shuddered violently, fighting the urge to vomit, struggling to banish those dark thoughts, those awful memories. She focused on her unblemished arms and hands. A weakened healing factor had left her with horrendous scars that had taken months to fade, long enough that she had thought they would be permanent. Eventually, though, all physical signs of that torture were gone.

The serum was a remarkable thing, she mused.

She shivered again, this time as much from the cold as from the horrors of the past, and she jumped badly when a blanket was hung over her shoulders.

“Sorry, Jax, I didn’t mean to startle you.”

Jax shook her head, willing herself to stop shaking. “’S okay, Miss Romanoff. Didn’t hear you come in.”

“Natasha. Please.” She gave her a genuine smile that flickered for the briefest moment at the paleness of the girl’s face, the dark shadows under her eyes, the fingernails digging harshly into her arms. “Are you alright?” she asked softly, kneeling on the floor in front of her.

Jax shook her head jerkily, gaze fixed on a distant wall.

Nat cupped her cheek with a hand, movements slow and deliberate, voice calm and soft, attempting to soothe the skittish child. “You haven’t been sleeping well, have you?”

Jax said nothing, only continued to stare at the wall.

Nat hummed to herself. “Nightmares?”

Jax nodded once.

“ _Past, present, or future_?” she asked in Russian.

The phrase pulled Jax back into sharp focus, and she blinked owlishly at Natasha.

Natasha blinked back. “What?”

Her lip twitched up. “Auntie Nat would say that to me any time I was...” She gestured vaguely at herself.

“All of the above,” Jax said quietly.

Nat nodded and motioned for her to scoot, squeezing into the armchair with her. She opened an arm invitingly and Jax immediately curled into her side, head tucked under Nat’s chin. “Would you like to talk about it?”

Jax shook her head. “The nightmares – ’S nothin’ new.” She hesitated, then said, “Not being able to go to Ma after – ” She took a deep, shuddering breath and Nat tightened her arms around Jax protectively. Jax leaned into the embrace, then pulled back a tiny bit, absently tracing invisible lines on her arms, particularly the inner wrists.

“Don’t tell Pop – Steve. Please.”

Natasha made sure her face remained neutral over the sense of alarm she felt watching her trace over what she was sure were once old wounds, self-inflicted or otherwise. “I can’t promise that, little one.” She took Jax’s hands in hers and pressed thumbs into inner wrists. “Not if you’re headed this direction. I shouldn’t be the only one looking out for you.”

Jax shook her head. “JARVIS has a protocol for it. Alarms would go off long before I could do anything.”

Natasha didn’t ask why such a protocol would even exist or how she knew about it.

“When’d you get back, anyway?” Jax asked suddenly.

Natasha took the change of subject in stride. “Earlier this afternoon.”

“Seriously? How didn’t I notice?”

“No idea, considering I was at dinner.”

Jax’s brow furrowed. “I guess I really was out of it. You woulda kicked my ass for being so inattentive.”

Natasha raised an eyebrow. “Even at home?”

“ _Especially_ at home.”

Natasha briefly considered broaching the subject of kidnappings, then decided against it. “I could still kick your ass, if you’d like.”

Jax flashed a wry smile. “If _I’d_ like, she asks.”

“If anything, it may help you sleep.”

“True. Alright, fine, just don’t hold back on me,” Jax said, stifling a yawn.

 

Natasha wasn’t sure what lead her to be so open with the girl – perhaps it was how open Jax had been with her in the first place. Spies had to have a certain knack for acting, and Jax showed every sign of being, maybe not a master, but pretty damn good when needed, able to adopt a poker face that rivaled most agents. She supposed other Nat and Clint had done more than train her in weapons and martial arts.

She wondered, not for the first time, how similar Jax’s Nat was to herself, and how much she had shared with Jax. She remembered the look on Tony’s face when Jax had whispered to him that first night. _I know you, Tony Stark_ , she had said. Did she know Natasha Romanoff as well?

She certainly knew Black Widow’s fighting style. Despite the lack of sleep and the resulting sluggishness, Jax was somewhat able to keep up, except Nat’s reach was longer and more often than not prevented Jax from hitting her mark or completing a take down. A foot or so taller and Jax may yet win against her.

 _I know you, Tony Stark._ She never talked about her mother – the one thing that was absolutely different about their worlds. It probably hurt her too much to think about it, and not without reason. Something about the way she looked at Stark. Pain, certainly, and grief. Anger?

_I know you, Tony Stark._

Shit. Tony’s birthday was tomorrow. Today, she corrected, with a glance at the coming dawn.

No wonder the girl was in such a funk. Nat would have to warn Stark to keep the festivities at a dull roar, preferably away from the tower.

Finally, when Jax could hardly stand straight from exhaustion, Natasha lead her back to the common floor. “I would tell you to get some sleep, but you won’t.”

“You know me so well,” Jax yawned. “I’m thinking pancakes – blueberry – and a gallon of coffee. After a shower, of course.”

Natasha felt her lips turn up. “I’ll be there.”

 

True to her word, Natasha made her way back to the common floor not quite an hour later. Jax was at the stove, hair still wet, a giant novelty mug full of coffee within reach.

Steve was at the counter, sneaking the occasional pancake off the giant stack when Jax’s back was turned. Bruce attempted to do the same as he walked by, only to have his hand smacked with a spatula. “I’m almost done, Doc, you can wait. Pop, you steal one more pancake and I’m cuttin’ you off.”

Clint wandered in as Steve whistled innocently and Bruce rubbed his hand where it was struck. He grinned. “You should know better than that by now, boys.”

Bruce made a face and poured himself coffee, the mug overflowing when Tony entered the kitchen. Clint spun around dramatically to look at the wall clock.

Tony flipped Clint off and gave Bruce a withering look. “Bruce, quit wasting coffee.”

Jax stiffened very slightly at Tony’s voice. “Mornin’ Tony,” she said without looking up.

“Morning, kid. Ooh, blueberry!”

“Table set yet?” Jax asked, giving Tony a warning stare as he reached for a pancake. He yanked his hand back as though it had been burned and dutifully moved to set the table.

Steve and Clint looked at Tony, then Jax, then each other, eyebrows raised, then leapt out of their seats to help Tony. Bruce shuffled after them. Natasha rolled her eyes, and Jax grinned at her. _Boys_.

 

“So, Tony,” Steve said after his twelfth pancake, “When’s the last time you slept?”

“Last night.”

“You tellin’ me you’re up before noon on a weekend?”

“It’s been known to happen.”

“What’s the occasion?”

Tony glanced at Nat, who glanced at Jax, who seemed very engrossed in her food.

“It’s his birthday,” Jax said quietly, still staring at her plate. Tony frowned, and she shrugged. “What? Not saying it isn’t gonna make it any less true.”

Steve tilted his head for a moment, confused, then grimaced. “Jax –”

“Pop, please. Tony, it’s okay. Really. Eat your pancakes.”

Tony gave a little half-smile. “Thanks, Jax. Blueberry’s my fa – ” He cut himself off with a wince.

Jax snorted. “I know. Excuse me.” She stood up suddenly, leaving her plate and mug in the kitchen before walking out.

Tony sighed, chin dropping to his chest, then he turned his head to Steve.

Steve shook his head. “Shit, Tony, I’m sorry – ”

“She hasn’t been sleeping,” Nat said. “At least a couple days, probably more. She didn’t want me to say anything,” she added at Steve’s look.

Jax came back a few moments later, a large, thick envelope in hand. She sighed at their pitying expressions but said nothing until she reached Tony. “Something I’ve been working on,” she said, handing him the envelope. “Tradition, I guess you could say. I had a problem to solve each year for her - for her birthday.”

Tony opened the envelope curiously, pulling out a plain notebook. The writing on the first page was _tiny_ , lines upon lines of equations. He squinted at the paper, then at Jax, and put on his glasses.

“Geez, you’re old,” Jax muttered, leaning back in her chair.

Tony grinned and had JARVIS scan through the pages, pausing halfway through, slack jawed. “Is this – ?”

“Yep.”

“And you – ?”

“Yep.”

“You had to – ?”

“Every year.”

Tony made a delighted noise and flipped through the rest of the pages.

“What the hell is it?” Clint asked.

Jax stretched, tilting her chair back on two legs. “Tractor beam. Mathematical proof and blueprints for building one.”

Bruce looked at her over his glasses. “Tractor beam? Seriously?”

“A few years ago I had to solve the Riemann hypothesis. In comparison? This was a snap.”

Tony raised an eyebrow. “Riemann? You solved Riemann?”

“Nope. That was the year I lost the shield. Pretty sure Riemann was my punishment.”

Tony's grin was enormous. “Jax, thank you, this – this is pretty damn cool.”

Natasha observed from the kitchen as an ecstatic Tony fired questions at Jax. She answered grudgingly at first but within five minutes her enthusiasm mirrored Tony’s. Bruce listened intently, occasionally interjecting with his own questions. Steve and Clint gradually trickled out of dining area, only able to handle so much science that didn’t include explosions.

 

Rhodey stopped by later that day, fully prepared for a night of hard partying and a high likelihood of having to wrangle a plastered Tony back to the tower before or shortly after doing something stupid. He was most definitely not prepared to find Tony completely sober, still in pajamas, sitting in his armchair and taking notes as Jax stood on a coffee table, lecturing him and Bruce on the properties of acoustic radiation.

“Are you – are you serious right now?”

Tony shushed him noisily and waved at Jax to continue.

 

 

 

 

**Notes for the Chapter:**

> I am by no means a mathematician, but vaguely remember learning about the Millennium Prize Problems in high school and was known to enjoy solving algorithms for extra credit. 
> 
> I like the idea of little Jax not knowing what to give her mom for her birthday, so Andrea Stark jokingly asked for a [fill in the blank] and was flabbergasted when Jax presented her with complete blueprints at her birthday breakfast. 
> 
> (She would have actually built it, but only had a couple weeks until her birthday and ran out of time.)
> 
> After that, it was tradition for Andrea to ask Jax for something ostentatious on her birthday, and for Jax to present her research the following year.


End file.
